Wet-coal mill



1. M. SCHUTZ.

WET COAL MILL.

APPLICATION FILED JAN. 28, i918. 1,338,845. Patented May 4, 1920.

8 SHEETS-SHEET l I. M. SCHUTZ.

WET COAL MILL.

APPLICATION FILED JAN. 28. 19,18.

Patented Mayli, 1920.

8 SHEETS-SHEET 2.

I. M. SCHUTZ.

WET COAL MILL.

APPLICATION FILED IAN. 28. |918. 1,838,845. Patented May 4, 1920.

8 SHEETS-SHEET 3- a 5E I "I 'i ma J. M. SCHUTZ.

wET coAL MILL.

Patented May 4, 1920.

8 SHLETS-SHEET 5.

fm f 5 fm A 0 3 6 i N Q 6, /7 7 8 u J I?? C j 4@ 7 W I, M e l J m E. I II IDT C J. M. SCHUTZ.

WET COAL MILL.

APPLICATION FILED JAN.28.1918.

1,338,845, Patented May 4,1920.

8 SHEETS-SHEET 6.

J. M. SCHUTZ.

WET COAL MILL. ArjPucATloN FILED um. 2s. 191s.

Patented May 4,1920.

` a SHEETS-SHEET?.

J. M. SCHUTZ.

WU COAL MILL. APPLICATION FILED .IAN-28.1918.

1 ,388,845, Patented May 4, 1920.

8 SHEETS-SHEETI 8.

UNITED STATES PATENT oEEioE.,

JOSEPH M. SCHITTZ, OF CII-IICAGO, ILLINOIS, ASSIGOR TO SCI-IUTZ I-IAWLEY COMPANY,

Y OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

WET-COAL MILL.

Specification of Letters Patent.

Patented May 4, 1920.

Application filed January 28, 1918. Serial No. 214,133.

To all whom t may concern:

Be it known that I, JOSEPH MARTIN SCHUTZ, a citizen of the United States, and a resident of Chicago, Cook county, Illinois, have invented a new, useful, and Improved Method and Apparatus for Milling Coal and the like, to which I have given the gen-A larly, from an aggregate of both coarse andv ine particles, down to a uniformly powdered or impalpable condition; without resort to or dependence upon any drying of the material as a preliminary `orintermediate step or incident in the milling operation.

A furtherobj ect of my invention is finally to condition the more or less wet finished product (the aggregate or the fine powder) by drying itto any extent required for its convenient and economical use, or storage.

It is to be understood that my invention is intended for use with coal in any state; whether wet', or dry; fine, or mixed, or in all-lumpform.

In most cases the invention will be used in milling f naturally moist mine-run coals of various kinds and blends, which contain large and small lumps', plus the portion more or less pulverized in the mining and handling operations.

In carrying out my invention I feed the coal as a stream which is substantially constant, except as affected by the presence of many or few lumps; and, constantly or continuously reduce the coal, thus supplied, to any desired predetermined finished form; all in oneoperation.

The reduping or milling process is continuous; and this, whether the material be wet or dry; and as will appear, the operation is as rapid in the one case as in the other. Furthermore, the process is not hindered by the presence of any normal amount of slate or of pyrites in the coal, for both yield to the forces employed almost as rapidly as does the coal.

rlhe coal from the primary feeder is received into a mechanism, which is a combined coarse breaker and secondary feeder. rIhis mechanism is of such construction that the already fine material and the semi-reduced material may pass directly through it without imposing an appreciable load upon the breaker, while the latter acts upon and retains the lumps until they also are reduced to at least a semi-finished state.

In this breaker and secondary feeder I take advantage of the fact that even very wet mine-run bituminous coal may be indiscriminately pulverized, crushed, or broken down to pass a coarse mesh screen or grate without becoming so pasty (with liberated moisture and fine dust) as to clog the mechanism or render its operation difficult.

The moist, semi-finished material, including much fine material, is delivered in substantially constant volume vby the second feeder and may be considered as comprising a second stream of material flowing at the relatively low rate of speed determined by the rate of feed at the primary feeder. Obviously, this stream of semi-finished material varies somewhat according to the volume and the regularity of the initial feed; and again, many large lumps may be received from the primary feeder, and at other times coarse or fine, according to the distance bel tween the rolls.

The two rolls, preferably, are of the same diameter;y and, in any case, I impart to them as nearly as possible the same peripheral speed. By so doing I- avoid or suppress the cutting, grinding, and scoring effects which so objectionably diminish the durability of the differentially speeded roll pairs now used in this and kindred arts.

I find that with bituminous coal good results are secured from rolls having a peripheral speed of twelve thousand feet per minute. Thus far I have found no practical limit to the speed, other than the strength of the rolls to resist the destructive effects of lcentrifugal force and any lack of exact balance. These factors obviously vary with the nature of the materials cornposing the rolls, the diameter of the rolls. and the nicety of the machine work upon the rolls and their bearings.

Ordinarily I do not find it necessary to vary the predetermined speed of any single machine; nordo I find it necessary to resort to use of belts for driving the rolls; preferring, as will appear, to use the constant or fixed speed, direct connected electric, steam, or gas motors, or turbines, for drlilving both the breaker and the high speedY ro s.

The width of the crack or opening between vthe smooth rolls determines the size ofthe largest pieces which will be found in the finished product. If the space is, for example, one thousandth of an inch (and this is a practicable dimension) the product will be an extremely fine powder; wet or dry according to the starting material; and finer than thus far required in any industry with which I am familiar. IlE the opening is wider, particles of that size will appear in the finished aggregate along with a proportionate amount of 4smaller picces,and a proportion of very fine material.

By my method of operating the rolls at the extremely high peripheral speeds indi cated, I secure the centrifugal riddance or discharge of all'material and water from the faces of the rolls, and thus maintain them in clean, perfect Working order at all times, without using Scrapers, wipers, or

brushes upon the rolls; indeed, and by way of contrast with former practices, the highspeed rotation of the rolls makes fit impossible to use such accessories thereon be cause the frictional heat generated would destroy them. v

A marked advantage'of the spaced-apart i smooth rolls is that particles of material already smaller than the space'between, the rolls, fall or are'projected through the opening without effecting an appreciable load upon the rolls or resisting their rotation. The extent of this advantage will be appreciated when it is understood that in the case`y of the ordinary coal aggregate, about seventy-five lper cent. of the semi-finished bulk from the secondary feeder is composed of these smaller particles, leaving only about Ordinarily, even the largest semi-finished pieces or lumps do not greatly exceed .the width of the opening between the rolls, and hence as they fall from the breaker and feeder they are instantly' grasped by the rolls at a level only slightly above the horizontal plane of the axes ofthe rolls; that is, at a poi-nt where theroll tangents approach at an acute angle. In consequence, the opening action o f the rolls is exercised at an extremely favorable leverage, and this, plus .the tremendous speed at which the rolls operate, results in the crushing of the small lump or piece by a squeezing action, so sudden as to amount to aV sharp blow; whereby the lump is caused to burst into many parts. From this it will be apparent that the proportion of coarse material found in the aggregate is determined not so much by the direct breaking action or impact of the rolls, as by the width of the opening between the rolls; for it will be obvious that pieces which are too large to freely fall through the opening, are instantaneously shattered into pieces much smaller than the opening.

`In eff'ectthe high-speed rolls constitute a live screenwhich not alone allows, but also` a baffle wall or breaker-plate beneath the rolls to receive the first impact of the forcibly ejected material.`

The high speed rolls, due to their momentum or kinetic force, admirablyabsorb all normal irregularities in the feed of the material, and compensate for variations in the nature (hardness) of the material.

In my method there is no handling of 'the material over and over again, as in 'ordinary pulverizing processes; the mill is at no time required to act upon a bank or mixed mass of material, and there are no tailings to be returned and re-milled. In consequence, the power consumed is only a frac tion of that hitherto supposed and found to be necessary.

The material having been finished in a wet state, which precludes its ignition by sparks or even by fiames within the mill or pulverizer, is deposited, preferably upon a conveyer which takes the material to the point of use, or to storage bins o'r to cars.

tion is desired, I utilize this force by fixing als -of parts;

IIhis I deem to be the proper procedure with any aggregate or powder than can be economically used or burned in its wet or moist condition; but for some uses the product should be .partially dried; and for othery uses should be completely deprived of its moisture. In such cases I dry the finished product as fast as it comes from the mill', preferably by converting the conveyer into va drier. As will appear, this is easily accomplished by heating the conveyer, or by inclosing it in a heated chamber and providing means for gently exhaustingthe steam which rises from the coal on the moving conveyer, or equivalent mechanism. In special cases, the finished and dried product from the conveyer should be used promptly or stored in a manner to prevent subsequent excessive absorption of moisture.

Obviously, the method and machine here described may be used in milling dry'coal and like non-gritty materials; but, in the case of any material as explosive as coal, it is of decided importance that the coal need not be dried at all until its pulverization has been completed, and that the product may thereafter be dried at non-igniting temperatures, under positive and easy control, and therefore without danger.

The chief advantages of mills which embody my invention and whereby I carry outthese processes, are their comparatively low cost. their great capacity, their relatively small use of power, their advantageous application of power, their compactness, dustlessness, and durability, the certain delivery and uniformity of their products. and the ease with which repairs can be made.

Embraced within the methods and the mill or apparatus, described in the foregoing, are several incidental steps and many features of construction7 and combinations all as hereinafter described and particularly pointed out in the appended claims.

My invention will be more readily understood by reference to the accompanying drawings that form pa'rt of this specification and in which:

Figure 1 is a diagrammatic illustration of my method and' machine for milling wet coal Fig. 2 is a sectional detail on the line 2-2 of Fig. 1 ;Fig. 3 is an end elevation of the mill proper ;-Fig. l is a sectional detail on the line 4--4 of Fig. 13, the dimensions being those of Figs. 3 and 7 ;-Fig. 5 is a side elevation of the mill ;-F`ig. 6 is a plan view;-F'ig. 7 is a sectional detail on the line 7-7 of Fig. 3 ;-Fig. 8 is a vertical section on the line 8-8 of Fig. 5;-Figs. 9 and 10 are enlarged sectional details illustrating the manner of forming and attaching the hammer-heads of the breaker roll or drum ;-F`ig. 11 is a horizontal section on the line 11-11 of Fig. 8 ;-Fig. 12 is avertical section `on the line 12--12 of Figs. 3 and 8;Fig. 13 is an enlarged vertical section on the line 13--13 of Figs. 3 and 8;--Fig. 14 is an enlarged partial end view and section von the line'14--14 of Fig. 13 ;and, Fig. 15 is an enlarged partial section on the line 15-15 of Figs. 1Q and 13. Y

No attempt will be made to set forth herein all of the possible uses of the several steps of my' novel method or process; nor all of the ways in which my mill may be constructed for use with' different grades of coal, nor in different situations. Such other uses and constructions will readily suggest themselves to those who are skilled in the several branches. of the art.

In describing my method I shall refer first to Fig. 1 of the drawings, in order that the several elements of a complete apparatus or plant may be quickly distinguished and understood; after which, I will explain the construction of the mill proper, in detail; and (eo-incidentally my complete method, as exemplified in the milling of wet coal by means of the plant illustrated.

As depicted in Fig. 1 of the drawings, A is the beforementioned primary feeder ;-B is the breaker feeder or as it will be called herein, the secondary feeder ;-C is the pair of high speed rolls;-D is a rotary valve which I prefer to use for the discharge of the mill ;-E is the drier containing the conveyer, F, and a heater, E, and having a discharge conveyer, G, for the finished, dried product ;-and, H is a suction fan which removes the moisture evaporated from the material on the conveyer. The elements, B and C, are arranged within a housing or frame, I, and'therewith constitute the mill proper. This machine (hereinafter called simply the mill) is secured upon a suitable foundation, J, and preferably straddles the drier, E. Frames, A', and, H', support the primary feeder and the exhaust fan.

The material to be milled being, in the assumed case, mine run coal, K, in the natural moist condition, enters through the trunk A2, of the primary feeder. Preferably the feeder is also a magnetic separator of approved form. Its chief elements are a magnetized pulley, 1, an inert pulley, 2, and a conveyer belt, 3, which runs on the pulleys, 1 and 2. The pulleys are slowly driven by means of a suitable variable speed motor (not shown) and the device is adapted to forward or feed the coal as a substantially constant stream, which varies in volume only as the speed of the motor is varied by the operator. .The parts, 1, 2 and 3, are inclosed by a dust housing, 4. `This has one discharge openingf, for the coal, and another. 6, .for the pieces of metal magnetically extracted from the stream of coal.

The coal may fall directly from the priausA mary feeder into the tan ential throat, B', of the secondary feeder. he chief elements of this secondary feeder are the .heavy breaker roll, B2, and a cylindrical casing, B3, preferably eccentric to the roll and having its bottom formed by a grating, B. The breaker roll, B2, is rotated at high speed, and this, co-acting with the surrounding walls of the casing, shattersI the coal as rapidly as it enters through the throat, B1. The coal thus shattered, together with material already fine in themine-run product. passes through the grating, B, in, what .I have termed, a semi-finished state, in .which it is adapted for final reduction by the finishing rolls. In other words, the element,

B, is a feeding mechanism which performs the double function of insuring the lreduction of all the coal to a semi-finished condi tion and continuously feeding it to the finishing rolls, C. Obviously the size of the largest pieces of the semi-finished stock is determined by the spacing of the bars which form the grating, B.

'A hopper formed by walls, B5, and the roll saddle, C', serves properly to confine the semi-finished material and direct it upon the rolls, C. Dust cannot escape from the breaker-feeder, for, as shown, that element is inclosed by the housing, I.

The rolls, C, C, preferably are heavy, and of large diameter. I prefer that their sur-- faces shall be smooth, but, as before stated,

I may make use of fine longitudinal corrugations therein for some materials, 'and particularly where circumstances make it desirable to employ high speed rolls of comparatively small diameter. But the action the finished product.

gaged by of the rolls will be better understood if they are considered in their best form; that is, as having smooth surfaces. These rolls are independent; and are held outof contact. Therefore, neither one accelerates or retards the rotation of the othe'. For the usual milling of coal the width of the space or opening, C2, may var from a quarter of an inch to a just-out-o -contact condition, according to the degreeof fineness required in These rolls are rotated at as nearly as possible the same speed, and at very hgh speed. The means by which the rolls, are rotated preferably comprise two independent high'speed connected motors ;-one for each roll, as hereinafter explained.

The capacity of the inishing'rolls, as their high peripheral speed and the` size of the opening between them, exceeds the capacity of the secondary feeder; hence there is no banking of material on the rolls, C. Therefore the semi-finished material may be, referred to as falling or flowing from the-secondary feeder' at one Speed and as being caught and projected, or

expeled, by the rolls, C, at a much higher spee The ne material received from the secondary feeder readily passes through the opening, C2, between the rolls without further material reduction thereby. There are two reasons for this: First, the opening between the rolls is large enough to liet the small particles pass freely; and, second, the rotating rolls create a strong downward suction which imparts to the 511e particles a speed approximating the peripheral speed of the rolls, whereby the fine material, in the mainfis forcibly drawn intoand then ejected from the opening between the rolls without being materially impeded by the accompanying larger particles.

e coarser particles fall as far as they may between the rolls, and, being there caught between the rolls, are instantaneously 4'shattered and expelled downward through the opening, C2. owever, wet the semiiinished product, K', may be, it is in this manner caught by and ejected from the rolls in the finished state, indicated at K2. Coincidentally, all particles of material and all liquid which, except for the high speed, would adhere to the rolls and thereby quickly render them inoperative, are forcibly detached therefrom by centrifugalforce. In this manner, that is, by rotating the rolls very rapidly, the surfaces of the rolls are kept clean and dry without the aid of accessory cleaners or wi ers of any kind.

The finished coal, 2, is received by the hopper, I', which forms the bottom of the mill.- The opening of the discharge hopper, I', is preferably equipped with the rotary valve or closure, D, for the avoidance of air drafts in either direction through the mill.

This suitably rotated valve, D, discharges the finished product directly upon the top of the drier-conveyer, F.

As indicated the high speed rolls create a strong movement of air between thesecondary feeder and the space below the rolls. In other words, the rolls, C, create a suction downward through the breaker and its gratn ing; and also create a pressure in the space beneath and surrounding the rolls (beneath the hopper walls, b5). To preventl the blowing of dust laden airy outwardly, through the bearings of the rolls, I prefer to provide the mill with an air relief trunk, L; and in most cases this relief will be augmented by a suction fan connected therewith. l

A conveyer; F, of some kind is usually required to carry the material from the mill tothe point of use or storage, and, as in many cases -it is desirable that the material shall be either partially orfwholly dried storedin open bins without danger shown, the drier, or retort, may comprise a closed chamber, Il, wherein the shallow conveyer I" is arranged in conjunction with a steam coil or other heater, E.

The conveyer runs rapidly in order to carry the material away in the form of a thin layer, in which condition it may be gradually and sufficiently heated at a low temperature, which in turn expels the water. I make the drier long enough to insure the complete drying of the coal before it is discharged from the end of the conveyer. By the means illustrated I ain able to dry the coal as rapidly as it is furnished by the mill and without evolving a cloud of dust, or a separation of line and coarse particles; and, furthermore, by maintaining only a low temperature in the elongated or longperiod drier I am able to dry the coal virtually without loss of any of its valuable volatile constituents, should I so desire. To prevent the condensation of the evaporated moisture u on the coal, I employ the exhaust fan, and its connections, H2, as a means to quietly exhaust all the vapor which rises from the material on the hot conveyer, F. By subdividing the suction in the chamber, E, in this manner I avoid raising even the finest dust from the conveyer; and incidentally I am able to recover the Awater as a clear distilled product, at the exhaust end of the suction fan, H Conversely, by increasing the temierature in the drier, or continuous retort, can very effectively distil off any desired proportion of the volatile gases of the coal, for which a valuable use can be found separate from-the combustion of the solids. i

In most cases, and particularly in the instance of coal for my furnaces, the coal will be discharged either in its natural state as to moisture, or in an only partially dry condition, and in such cases the coal may be and without annoyance from dust, the product being sufficiently moist to retain the dust. The use of the coal in this partially dried conditionwill also be found desirable from the standpoint ofthe saving of heat in the drier.

Obviously, the .construction of the arts shown in Fig. 1 may be extensively mo ified vand still retain the spirit and essentials of my invention. I prefer, however, that in practically every be used for milling coal it shall be constructed in substantial accordance with the detailed forms and relations depicted in Figs. 3 to 15 of the drawings. This is true even for large mills which are adapted to handle many carloads of coal per hour.

I have attained great success with a mill of the identical construction herein depicted and wherein the breaker roll, B2, is twentycase where the mill is to l. throughout.

four inches in diameter and twenty-four inches long; 'wherein each finishing roll,

C, is twenty-four inches in diameter and twenty-four inches long wherein each of the rolls mentioned weighs approximately one ton; and using constant speed, direct connected electric motors for operating the several rolls, the motor of the breaker i'oll being of twenty-five horse power and the motors of the finishing `rolls being each of five horse power, and all of the motors operating at approximately eighteen hundred revolutions per minute. The most efficient capacity of the mill inentioned is thirty tons of coal aggregate per as dissingle base which contains and supports all of lits other parts, andwhich base is sup ported by a single foundation. The base referred to is constituted by the before-mentioned frame or housing, I. This housing for ease of manufacture and the assemblage of the parts therein, is made in sections, as, for example, a bottom section, 7 a middle section, 8, and a top section, 9; parted upon horizontal planes, and all firmly bolted together. These sections are preferably rectangular in horizontal cross section. The distance between the sides of the housing is determined by the length of thecontained rolls, B2, and C, which dimension may be proportionately less, or'more', than herein shown; accor ing to the desired capacity of the mill. To enable the easy placing of the rolls, C, C, I provide rectangular openings, 11, in the sides of the base portion, 7. These openings are closedby light plates, 12, bolted in place, for further purposes herein explained.

The construction of the rolls, 0.--These rolls preferably are identically the same.

Each roll is nicely balanced, either by exactinitial manufacture or by meansI of weights added thereto when needed; a nice balance being necessary because of their speed of rotation. The crushing strength of coal in the semi-finished condition, above described is not reat,y and no great kinetic force is require in the rolls, C, to compensate for irregularities of feed. Therefore, I do not find it necessary to make the rolls solid Instead the roll proper, in

each case, is formed by a heavy walled shell or cylinder preferably madeJof manganese steel, and which is held centrally upon the complementary shaft, 13, by the disks or ends, 14 and 14. The'cylinder and the ends meet upon truncated cones, 15, formed thereon. Both heads are tightly fitted to the shaft and are also secured by keys, 16. The head, 14, is located by a shoulder 13', on the shaft; the other head, 14', though tight on the shaft, is otherwise free to adjust itself longitudinally. The parts are bound together by heavy bolt rods, 17, which pass through t e heads, 14, 14', and through notches or holes, 15', in the internal cone ribs of the cylinder, C. After being thus assembled the roll is nicely balanced, as before indicated. The ends of the shaft extend outwardly through relatively ,I'large elon. gated holes 12,.in the side plates, 12; the shaft has no bearing in either of these plates,

. 12 (see Fig. 14).

The means which support the rolls, 0.- The axes of the rolls are and should be parallel and in a horizontal plane. To adjustably support the rolls in this situation, I employ guides and cross-heads, arranging within the cross-heads fine anti-friction c bearings for the shafts, 13, of the rolls.

' held in blocks or v parts, 20',

Referring now to Figs. 3, 5, 6, 7, 11 and 13, itl will be seen that'I provide this cross-head equipment upon both sides of the mill housing or frame. Thus on each side are two parallel cross-head guides comprising sufficiently strong bars, 18, rigidly clamped and brackets, i 19, projecting horizontally from the sides of the base portion, 7 of the mill housing. These rods do not move. They are arranged in vertical planes, as nearly as possible perpendicular to the horizontal plane of the roll axes. Slidably, but otherwise rigidly held on the guides, 18, are the cross-heads, 20, two on each pair of guides; that is, two on each side of the mill. The portions, 20', 'form the slide bearings on the guides, 18, and present square shoulders to the hereinafter mentioned pressure springs, 21. Except for the each cross-head is preferably circular and in particular is provided with a circular face, 20", to serve as the base for a motor containing bracket, as hereinafter described. The ends of each roll shaft, 13, are borne in the opposite cross-heads, on the two sides of the machine. In each case the direct bearing between the shaftand the cross-head lcomprises an anti-friction ball bearing, 22, of approved construction, to-

gether with an indirect bearing which comprises a ball, 23,1 and socket joint. This 'forms a universal joint between the shaft and its cross-head. The ball .portion is a part of a sphere. the ball bearing, 22. In accordance with best practice, the inner ring of the ball bear- It is bored out to receive ing is fixed on the shaft between a shoulder thereon and an end nut, 27, threaded on the end of the shaft. The ball portion,23, is snuglyv but not immovably held ina comple-y mentary spherical cavity, 2 4, provided'. at the center of the cross-head, 20. A removable ring or section, 24', permits the insertion and removal of the ball proper, 23, and provides means for tightening the ball in the socket. In each ease, the ball and socketv connection between the shaft, 13, andthe cross-head permits a considerable degree of malalinement between those parts and thereby prevents the cramping of the relatively delicate ball bearing, 22. A felt washer, 25,

in each bearing serves to exclude dust from the lnner end of the bearing and the outer y prevented by the formation of a tight slid-' ing joint between each cross-head and the adjacent side plate, 12. To this end the inner side of the cross head is faced off; and the projecting part, 12, of the plate is faced to fit it. The joints secured in this manner are usually effective without the employment of interposed packings, but, if desired, the latter can be used between each cross-head and its sliding seat, 12". The only thing essential is that the cross-heads shall not be restrained by their engagement with the sides of the mill, but shall be free to slide upon the guide bars, 18. Obviously, the proper' arrangement ofthe roll shafts is that in which they are perpendicular to the vertical plane of the cross-heads. Supported in the manner described, these heavy rolls may be turned by an effort as slight as the pressure of a single finger of the hand; which, obviously implies that theymay be started into rotation bythe torque of a relatively weak motor, and, once started, may be kept in rotation by the expenditure of comparatively little power. At this point, I call attention to the fact that when rotated at the high speeds defined, these rolls, C, become gyrostats and tend to maintain their relative initial positions; a matter attached to each end of .each roll shaft, 13. But in most cases an adequate drive is secured at only one end of each shaft. As

illustrated, and chiefly to made the millas nearly as possible symmetrical, I prefer to drive one roll from one side of the mill and the other roll from the other. side thereof. Each shaft, 13, has a reduced end, 13, which projects through a dust proof hole in the bearing cap, 26. rThe motor, 28, is directly connected with the end, 13, of the shaft, through pling, 29. In the case illustrated, I employ constant speed electric motors of approved design. Any other form of high-speed motor may, of course, be substituted. Each motor is supported by its respective cross head, and therefore may be adjusted, and move with, its respective roll. 'Io this end I employ, for each motor, a bracket, 30, which takes the form of a cylindrical housing therefor and which is bolted to the outer face, 20"", of the cross-head, 20. The motor is fixed within the bracket, the latter serving as the sub-base therefor. Access doors, 31 and 32, are provided at the outer end, and in the side of the motor `housing or bracket; and to permit a proper circulation of air through the motor and at the same time exclude dust, these doors are perforated and provided with screens. The electrical connections for the motor enter the housing through an insulating block,l 33, provided in the side of the bracket.

T he'means for adjust/ag the rolls, 0.-- As previously explained, the rolls, C, are held out of contact. This is accomplished by means of retracting jacks that are coupled to the cross-heads of the rolls and whereby the rolls may be drawn apart to make the opening, C2, of any desired width, ranging between actual contact and the maximum separation permitted by the length of the elongated slots, 12', in the plate, 12. It may here be explained that these slots, 12', also permit the adjustment of the rolls toward one another to compensate for the wearing away of the faces of the rolls. The jacks prevent the closing to gether of the rolls'beyond the fixed distance;

but are so formed as to permit free separa-- tion of the rolls in event a large piece of metal, or the like, falls between them. This is a wise precautionin view of the fact that the grate bars, B4, are not indestructible, and a broken bar might otherwise wreck the finishing rolls. While the jacks hold the rolls apart, they are at the same time held firmly in their given positions by the action of the strong springs, 21, on the guides, 18, which press against the cross-heads. As best illustrated in Fig. 7 the pressure of these springs, 21, may be varied by means of respective spring follower nuts, 21', threaded upon the fixed guide bars, 18. As best the medium of a {iexible couvsprocket wheel, 36.

parallelism,

shown in Figs. 3, li, and 11, the retracting `ack of each cross-head comprises a rod, 34, aving its inner end fixed securely in a boss, 20, on the cross-head, and having its outer end, 35, threaded to receive the internally threaded hub of a sprocket wheel, 36. The intermediate portion of the rod, 311, is slidably held in a horizontal pillow-block, or bracket, 37, on the side of the mill base and against which the hub of the sprocket wheel bears. Obviously, each jack may be separately adjusted by rotating its threaded Except for the initial positioning of the rolls, such separate adjustment is objectionable. Therefore, I provide, first, for an initial adjustment by means of the lock nuts, 34', against the cross heads, and, secondly, for the simultaneous and equal adjustment of each pair of jacks. The simultaneous adjustment is secured by means of sprocket belts, 38, that join the sprocket wheels, 36, of respective pairs of jacks. Actual motion is imparted through a large lever or wrench (not shown) applied to the hub of one of the sprocket wheels. Obviously, by thus rotating the sprockets simultaneously the jacks may be lretracted equal distances or may be slackened under the influence lof the compression springs, 21. By these simple mechanisms I am able to adjust the two heavy rolls,v C, at equal distances from the middle plane of the mill, to maintain their l and to nicely adjust and maintain the width of the working opening, C2, between the rolls.

T he roll saddle, Ola-The saddle of my machine differs from those in common use, in that it co-acts with the extreme ends of the rolls, instead of overlapping them. cannot use the old constructions because such saddles, byprotecting the rolls at the ends, maintain those ends at their initial dimensions and thus prevent the taking u of roll surface wear. The saddle which I employ allows the wear to be uniform from end to end of the rolls, leaving`them always in condition for accurate adjustment. At each end of the pair of rolls, C, I provide a disk, 40, having its axis parallel with the rolls4 and in the middle vertical plane of the pair. The disk, as best shown in Flg. 12, is adjusted close to the end of the rolls and thus prevents material from passing over those ends instead of through the open' ing, C2. 'A single plate might be used at eachend, but there is considerable wear by the material which eventually cuts a groove in a plate so situated, the cut-groove coinciding with the V-opening between the rolls, and allowing the escape of some unfinished material. I therefore prefer the disk formation. By rotating the disk slightly from time to time the essential closure at the ends of the V of the rolls may be restored, the

.clamping bolts of the worn or cut-out' portion being moved to one side. To the end that each disk may be used in this Way, I prefer to mount it upon the head, 41, of a spindle, 42, which is held in the side plate, 12. A set screw, 43, is provided for fastening the disk after adjustment. Obviously, the two plates or 'disksclose the ends of the V-gap between the rolls and more effectively prevent the spillingI over of material than would saddles of the old type, at the same time exposing the full surface of the rolls to normal wear. The saddle is completed by a rectangular frame having perpendicular ends, 44, joined by the inclined hopper sides or extensions. The vertical parts are bolted to the inner sides of the plates, 12, 12. Segmental recesses formed in the the disks, 40. urther additions to the saddle comprise the adjustable plates, 45, which may be set close to, but not in contact with, the rolls, C, and which`may be yadjusted as said rolls wear down. The purpose of these plates 45 is to prevent the escape of material, which falling upon the rolls, either bounds therefrom or is thrown in the direction of the opposite hopper wall and might otherwise Manholes, 47, are provided in the ends ofA the mill housing; through .which the plates, 45, may be reached, and allowing access to the surfaces of the rolls, C, when necessary. f

The construction of the fea/ce1' casing, B3. The upper half, 50, of the breaker casing, together with the throat forming oportions, 51, is integral with and is partly formed by the casting or section, 9, of the mill housing, I. The internal walls, 50 and 50', are strengthened by heavy webs, 52, as required to take the heavy blows to which they are subjected. To prevent direct wear upon the internal walls of the casing I line the same with manganese steel castings or the like, 53, preferably sharply corrugated, as shown. The lower half of the breaker casing comprises the before mentioned grating B4. lThis grating is composed of a plurality of identicalbars, 54, lhaving squared ends, 55, held and preferably riveted in the curved cradle hangers, 56. These hangers are provided with ears, 56', and the grating as assembled is removably supported by means of two cross-bars or bolts, 57, which pass through these ears and which rhave their ends held in bosses, 58, formed on the sides of the sections, 8. Set'screws, 59, prevent the loosening of the grate or screen supporting rods, 57. By employing' bars, 54," of different sizes and spacing, the grating is adapted to the production of differ. `ent grades of vsemi-finished stock. Where a line finished product is tobefmade, a nar-V i `row spacing is used between the grate bars;

and where a coarse aggregate is to be proarts, 44, admit the tops of.

pass through one of the openings,

duced the grate bars will be separated by wider spaces. Obviously a single set of grate bars may be used in making up the different gratings, provided differently perforated hangers, 56, are furnished as extra parts with the,mill. The grate bars, 54, are preferably made of manganese steel, or like tough metal, and together form a somewihat corrugated open bottom for the breaker casing. The grating may be got out by removing the top section, 9,of vthe mill. It should he noted that the casing is slightly eccentric to the axis of the breaker roll, B2, whereby the space,67,between the inner periphery of the casing and the periphery of the breaker roll is given the form of a geometric volute, thus providing for a progressive reduction of material which is received between the two parts.

The construction of the breaker roll, B, is well disclosed in Figs.v8, 9, 10 and 12 of the drawings. As there shown, the breaker roll preferably comprises a plurality .of polygonal sections, 60,-set side to side upon the heavy shaft, 61, and keyed thereto in different positions whereby the polygonal parts are staggered. That these polygonal sections or disks need not be solid is indicated in Fig. 12. The first section, 60, is pressed against the shoulder, 61', on the shaft. The other sections are similarly placed on the shaft and then the last section lcontaining a slightly smaller shaft hole is 'roll which has a large number of tangential hammers. The .sections proper are not greatly worn by use, the rigid hammer blocks performing the essential work. When the hammers become worn, the rivets, 65, are sheared and knocked out, and new hammer blocks riveted in place on the lugs or anchorages, 62. The roll as a whole being rotated in the direction of theseham mers (as indicated'by the arrow in Fig. 8) it is obvious that the hammers successively strike the pieces and chunks of coal which enter through the throat, B1. Being rotated at high speed, the wholeweight and momentum` of the heavy roll backs the blow of every hammer thereof and in consequence material directly upon the top of the breaker roll, that is, it ,has an inclined bottom. G6, which is above the roll, and the top of the throat overhangs said roll. Every piece of the material struck by the hammers is in the main shattered before it reaches the upper or opposed wall, 53, of the casing, and, vstriking the latter at high speed, is further shattered by impact therewith. Thus the operation proceeds step by step, as the material progresses in the volute, 67. be fore mentioned. Material which enters the' throat in an already fine condition is not much reduced by the action of the breaker roll, but, being carried downward thereby, sifts directly through the feeder screen, B4, along with the material shattered by the breaker. Little, if any, coarse material is carried over, for the closely adjusted breaker or liner plates below the throat floor, 66, are effective to finally reduce lumps carried around to that point.

The means which support the breaker roll-On referring to Fig-1Q it will be noted that the shaft, G1, of the breaker roll, like the shafts of the finishing rolls, has ends which extend through and beyond openings, G8, in the sides of the mill housing. These openings are formed, half in part 8 and half in the part 9. The shaft is supported by anti-friction,-universal joint or self-adjusting bearings, contained by the large circular castings or disks, 69. Upon the sides of the parts 8 and 9 I form circular ribs, 70, and face these olf to provide seats-for the flanges, 69', of the circular plates, 69. The plates are bolted firmly in place on respective seats, 69". Incidentally the lbolted plates, 69, serve to firmly tie together and strengthen the housing parts, 8 and 9, in the immediate region of the breaker cylinder, where the mechanism is subjected to the severest blowsand shocks. As in the case of the finishingroll shafts, direct bearings for the shaft, 61, are formed by anti-friction ball or roller bearings, 71; and the indirect or universal joint bearing is in each case formed by a ball, 7 2, and' its socket, 7 3, in the plate, 69. As before there is a removable socket ring, 7 4, which secures the ball, 72, in place. Lock nuts, 75, secure the ball bearings in proper position on the ends of the shaft; and the ball bearings are inclosed and protected by end caps, 76, 76', respectively, in conjunction with felt washers, 77, that close the inlner ends of the bearings. The outer faces,

78, of the plates, 69, on opposite sides of the mill are faced and shouldered to receive the motor containing bracket, which therefore may be attached to either side of the mill, or a motor may be used at each end of the breaker roll.

The means for driving the breaker roll.- Except thatin most cases the motor, 79, of the breaker roll will be somewhat larger `than the motors of the finishing rolls, the

driving arrangement for the breaker is identical with the drivers described in con* junction with the finishing rolls. That is, the motor, 79, is contained and supported by a cylindrical bracket, 80, bolted to the face, 78, of one of the main blocks, or plates 69. There is a flexible coupling, 81, between the motor armature shaft and the extension, 61, of the breaker shaft, 61. The 'screened doors and electric connections belonging to the bracket, 80, are of the same design as like parts of the lower brackets; and are indi.- cated by corresponding numerals, 31a, 32a and 33% Thus supported and connected with the rotor (whatever its kind) of the motor, the breaker roll is adapted for rotation at high speed by minimum power. lVhen once i set in rotation the roll tends to maintain its axis; and particularly, the gyrostatic force incident to its rotation is a marked factor in the protection of the ball or roller bearings from the effects of the heavy impacts between the roll and the material which it encounters in the breaker casing.

The mill as a whole has a substantial and pleasing appearance. Its operation is substantially non-vibratory, noiseless, and dustless. No moving parts are exposed to endanger persons working around the mill. Thesel are marked advantages which should be tabulated in connection with others already recited.

When electric motors are used as the drivers for the breaking and finishing rolls, it is an easy matter to protect the machine by the mere use of proper fuse plugs in the electric supply lines of the motors. If the primary feeder is improperly operated and there is a tendency to clog the mill, or if a large piece of metal by chance enters the breaker, or if through error a quantity of material is allowed to bank on the finishing rolls, the excess load upon the motors causes the blowing of the fuse plugs and stops the motors before any damage results to the mill.

The best way in which to start the plant into operation is as follows -The finishing rolls are first set into rotation, by starting their motors, and they are permitted to attain their normal or high speed. The breaker roll is then similarly started into action. At the same time the valve, D, vthe conveyer, G, and the fan, H, are started. The plant is then ready to receive the material to be milled, whereupon the primary feeder, A, is set into operation, and, there being a supply of material, K, in the trunk, A?, the milling operation is instituted and thereafter is automatically maintained as long as the primary conveyer continues to bearings of the moving parts to see that they are properly. lubricated.

The most important use of my invention will be at the coal mine, where the whole product ofthe mine may, be thus cheaply and quickly reduced to a condition which 'not,only fits the coal for most economical use, particularly in my introgenerative furnaces, but also conditions it lto be handled and transported by means'and in ways which insure great savings over the present s'ystem of handling coal at the mines.

lt is understood that the specificunethod and'mechanism hereinafter described have Ibeen disclosed merely for purposes of illuslclaim as new and desire to secure/'by Letters i Patent The method of milling material as described, which consists-in feeding the crude material as a continuous stream, forcibly screening out the finer particles and -simultaneously reducing the larger pieces to a degree short of a pasty condition, whereby the Wholebulk is forwarded as a Q semifinished stock, screening the semi-finished stock between rolls that are separated by a space as wide as the thickest pieces in the finished product are to be, and smaller than the larger pieces `in the semi-finished stock, rotating said rolls.. at speeds which cause them to centrifugally clear themselves of solids and liquids and also causing the rolls to act as impact members and burst the larger pieces of' semi-finished stock and discharge the bulk of material as finishedstock, irrespective of its contained moisture.

2. The method of milling materialA as described, which consists in feeding the crude material as a continuous stream, forcibly screening out the. finer particles and simultaneously reducing the larger pieces to a degree short of a pasty condition whereby lthe whole vbulk is forwarded asa semifnished stock,'screening the semi-finished stock between rollsv that are separated by aspace as Wide as the thickest pieces in the finished product are to be, and smaller than thelarger. pieces in the semi-finished stock, .rotating said rolls at speeds which cause them to centrifugally clear themselves of solids and liquids and also causing the rolls to act as impact members and burst the larger pieces of semi-finished stock and dis- Y charge the bulk `of material irrespective of 3, The method of milling material as described, which consists in feeding the crude material as a continuous stream, forcibly screening lout the finer particles and simulta-neously. reducing the larger pieces to a degree short of apastygqndition, whereby the whole bulk is forwarded @is 'a' semi-finished stock, screening the'semi-finished stock between rolls that are separated by a space as wide as the thickest pieces in the finished product are to be, and smaller than the larger pieces in the semi-finished stock, rotating said rolls at speeds which cause them to -centrifugally clear themselves of solids and liquids and also causing the rolls to act `4 as impact members .and burst the larger pieces of semi-finished stock and discharge the bulk of material as finished stock, irrespective of its contained moisture, and finally drying the finished stock to a desired extent.

4. The method of milling material as de-'i scribed, which consists in feeding the crude material as a continuous stream, forcibly screening out the finer particles and simultaneously reducing' the larger pieces to a degree short of a pasty condition, wherebythe whole bulk is forwarded as a semifinished stock, screening the semi-finished stock between rolls that are separated by a space as wide as the thickest pieces in the finished product are to'be, and smaller than the larger pieces in the semi-inished stock, rotating said rolls at s eeds which cause lthem to centrifugally c ear themselves of solids and liquids and causing the lrolls to act as impact members and burst the larger pieces of semi-finished stock and discharge the bulk of material, irrespective of its moisture and then drying the finishedy stock to a desired extent, andlinally recovering as byproducts the constituents distilled from the stock by the drying heat.

5: The method of milling moist coal, which -consists inl screening the moist coal l between substantially smooth rolls that are separatedb'y a space as wide' as the thickest pieces in the yfinished product are to be, and smallerthan the lar e pieces of starting material, rotating sald rolls at speeds which cause them to centri'fugally clear themselves of solids and liquids and also izoJ causing the rolls to act as impact ymembers j and burst. the larger pieces and discharge the whole bulk of material, irrespective of the restraint of contained moisture and at a speed approximating VAthe peripheral speed L of said rolls.

6. The method of millingimoist coal,

smooth rolls .ing

-nished product are to be,

continuous stream, between substantially that are separated by an openthickest particles in the rotating said rolls at speeds which cause them to centrifugally clear themselves and to act as impact members upon the stock and discharge the whole bulk in a finished state.

7. The 'method of milling moist coil, which consists in feeding the moist coal as a continuous stream, between substantially smooth rollsthat are separated by an opening as wide as the thickest particles in the finished product are to be, rotating said rolls at speeds which cause them to centrifugally., clear themselves and to act as impact members upon the stock and discharge the whole bulk at a speed approximating the peripheral speed as wide as the of said rolls and causing thestream of stock from the rolls to'im` pvact a surface, which further pulverizes 1t.

8. The method of milling vset coal, which consists in feeding the wet coal as a continuous "stream, to asemi-inished state short of a pasty condition, whereb the whole bulk is forwarded as a semi-finis ed stock, screening the semi- 'finished stock between rolls that are sepawide as the thickest rated by a space as product are to be, and

pieces inthe finished forcibly reducing the coal smaller than the larger pieces in the semi;A

finished stock, rotating said rolls, at speeds which cause them to centrifugally clear themselves of solids and liquids and to act as impact members and burst the larger pieces of stock and discharge the whole bulk thereof in a finished state.

9. The method of milling wet coal, which consists in feeding the Wet coal as a continuous stream, forcibly reducing the coal to a semi-finished state short of a pasty condition, whereby the whole bulk is forwarded as a semi-.finished stock, screening the semifinished stock between rolls that are separated by a space as Wide as the thickest pieces in the finished product are to be, and smaller than the larger pieces in the semifinished stock, rotating said rolls at speedsv which causes them to centrifugally clear themselves of solids and liquids and to act as impact members and burst the larger pieces of stock and discharge the whole b ulk thereof in a finished state of reduction, continuously drying the product from the rolls and recovering the constituents distilled by the drying heat. V

In testimony whereof,- I have hereunto -set my hand thisv 22d day of January, 1918...

JOSEPH M. SCHUTZ 

